What kind of timing are you running ? a 383 bone stock in 66 charger with a good tune and 600 Holley DP carb my buddy had in high school was faster than any of the late 80's cars my other friends had at that time a rusty old charger wupin 305 camaro and mustangs on the street HA HA! Retarded timing , broken vacuum advance , Clogged fuel Filter . These things i would look at closely first.
